This high-quality stress path triaxial system is afully automatic system consisting basically ofa Bishop & Wesley cell which controls stressdirectly on the sample, three volume pressurecontroller(VPC), internal submersible load cellto measure axial load, a pressure transducerto measure pore water pressure and a lineardisplacement transducer to measure verticaldisplacement.
Thanks to the integrated software and alsokeyboard controller (volume pressure controller),the operation of the device is very user-friendly.Exchangeable, pre-calibrated measuring sensorsguarantee high accuracy over a wide measuringrange. All the tests are running under PC controllike stress path, K0, slow cyclic and etc.
This system needs 3 volume pressurecontrollers for axial load (lower chamber), cellpressure and one for back pressure. The celland back pressure can be alternatively providedby a dual channel APC (pneumatic controller)and would be upgraded to 3 channels forunsaturated tests if required.
GEOsys software in combination with this unitperforms all your tests automatically and withoutoperator assistance during the test period. The device meets or exceeds requirements of allinternational standards; namely ASTM, BS, EN,DIN and etc which are listed at Standard sectionof this document.
General Description
Bishop and Wesley (1975) developed a simple and versatile hydraulic triaxial stress path cell, which iscalled the Bishop and Wesley cell. The hydraulic pressure inside the lower pressure-chamber appliesthe axial stress in the stress path cell. The cell chamber (upper) and the lower pressure-chamber areall sealed with belloframs and the loading ram is placed between these two chambers.
This system needs 3 Advanced volume pressure controllers for axial load (lower chamber), cellpressure and one for back pressure. The cell and back pressure can be alternatively provided by adual channel APC (pneumatic controller) and would be upgraded to 3 channels for unsaturated testsif required.
The device is equipped with advanced GEOsys software which gives the possibility to users to run allthe test stages completely automatic and there is no need pf pretense of operator during the test.
System Geography
① Bishop and Wesley triaxial cell
② Submersible laod cell
③ Linear displacement transducer
④ Automatic Volume Pressure controller (VPC) for closed-loop control of axial stress and strain
⑤ Automatic Twin Volume Pressure controller (VPC) for cell pressure and back pressure control
⑥ Pressure transducer to measure pore water pressure and B-value check
⑦ Advanced data acquisition system for additional transducer
⑧ Software enables all kinds of stress paths and other tests
Bishop And Wesley Triaxial Cell
This cell is a Static Stress Path Hydraulic Celland does not need any conventional loadframe to supply axial stress as the verticalload is applied from lower chamber by using apiston and hydraulic pressure. The cell and thelower pressure-chamber are both sealed withbelloframs.The hydraulic pressure is suppliedby Advanced volume pressure controller. applied load on sample depends onthe size of piston area and pressure ofthe Advanced volume pressure controller.
The hydraulic fluid is water and by controllingthe pressure inside the lower chamber bothaxial displacement and force may be controlledtherefor the accuracy of the Pressure controllermeans here.The triaxial cell is a rigid triaxial cell with an internalframe (tie-rods) to connect all submersibletransducers directly at the sample before the cellis closed by the cell-wall.
Single Type Volume/Pressure Controller
Automatic Electromechanical pressure volume controller is a syringe pulse-less pump which generate and regulate pressure and provide flow control in a variety range for different applications e.g. cell pressure, back pressure or air pressure for unsaturated tests.
Different modes of pressure control e.g. constant pressure, pressure ramps, constant volume flow is available with using of this pump. It has Compact and space saving design (for wall-mounting or table use) and has different modes of pressure control (e.g. constant pressure, pressure ramps, constant volume flow).
Two of these pumps generate axial hydraulic loading and back pressure and in combination with a Pore water pressure transducer and software are used to run automatically all types of required tests which are pre-programmed in software.
Static Controller
The MultiCon is a compact data logging system which is developed for capturing 4, 8 or 16 electronic measuring sensors with an analogue output signal (±0-10V ) and converting them into a digital measuring signal which is subsequently transmitted to a PC for storage purposes. It is a 13-bitcontrol (optional 16-bit) and data acquisition unit. This way, numerous measurement values can be captured, e.g. force, distance and pressure of static processes.
The measurement data is captured continuously and can simultaneously be viewed via the optional data capture software (GEOsys) and made available in ASCII format. From there, the data can be fed into any evaluation programme.
The data conversion terminal –as pictured in the example– _is used to connect up to 8 transducers(sensors with built-in preamp/measuring amplifier).
The analogue inputs for the transducers are located on the back of the MultiCon with a supply voltage of 24 V. The inputs are for transducers with a standard signal output of ±0-10 V (optional±0-2.5 V or ±0-5 V also available).